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What should I consider in choosing a RAID array for InfoChannel 5?
Hardware FAQ Solution #19, Raid Arrays (last modified 06/01/2007):
Fast hard drives (10 or 15,000 rpm)
2x 5,400 or 7,200 RPM drives in a RAID-1 configuration where the RAID-1 controller does an effective "RAID-0 for reading" vs. a single 10,000 RPM drive the RAID-1 solution with the 5,400 RPM drives would be considerably faster and more secure (it is in fact RAID-1). Depending on the capacities especially now that there are chipsets with such RAID-1 built into their "SouthBridge" parts it will be cheaper.
Drives that are "too large" are also not a good idea (ignoring the "backup issue"--a 1TB drive can not be effectively backed up). There is the simple issue of "Head Settling Time" where there higher capacity drives are in effect slower than their lower capacity cousins, which why professional/industrial DataBase Servers generally use small fast RPM drives, which is why 73GB/15,000 RPM HDD's are so expensive.
Using RAID
The proper RAID level is important!
Note: For a Content Manager, RAID-5, (or RAID-6), is about the singularly the worst possible HDD configuration.
Using today's hardware our suggestions are:
Players:
RAID-1 (two drives) -- Security
RAID-1+0 (four drives) -- Security and performance!
Content Managers:
RAID-1 (two drives) -- Security
RAID-1+0 (four, six, eight, etc. drives) Security and performance (very high levels of performance with extreme "width").
RAID-5+0 (six drives minimum--two three drive RAID-5 packs stripped between them--this can go to "very wide"--example: 12 drives implemented as four RAID-5 packs and then RAID-0 striping between the packs!)
We are a firm believer in "Storage/Function File System Isolation". The OS would be on a small RAID-1 pack--a pair of 40 or 80GB HDD's in RAID-1. Data would be on an independent data back. For very high transaction Content Manager 5's the Transaction Logs for the Database would be on their own RAID-1 pack (independent of the DB).
Very high capacity Content Manager 5:
40GB, (two drives)RAID-1, BOOT;
40GB, (two drives)RAID-1, SWAP, TEMP, Database-TRANSACTION LOGS;
80GB, (four drives)RAID-1+0, DB;
1TB, (six drives, 250GB each)RAID-5+0, Media Assets, Logs.
This type of configuration is now rather simple because of the introduction of 2.5" SAS drives and the 5.25" enclosures that permit eight such drives in a 5.25" FH drive bay.
Regards,
Scala Technical Support
